Horton

Re: fdatasync performance problem with large number of DB files

Fujii Masao <masao.fujii@oss.nttdata.com>

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From: Fujii Masao <masao.fujii@oss.nttdata.com>
To: Thomas Munro <thomas.munro@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Michael Brown <michael.brown@discourse.org>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2021-03-18T06:13:16Z
Lists: pgsql-hackers 

On 2021/03/17 12:02, Thomas Munro wrote:
> On Tue, Mar 16, 2021 at 9:10 PM Fujii Masao <masao.fujii@oss.nttdata.com> wrote:
>> Thanks for the patch!
>>
>> +        When set to <literal>fsync</literal>, which is the default,
>> +        <productname>PostgreSQL</productname> will recursively open and fsync
>> +        all files in the data directory before crash recovery begins.
>>
>> Isn't this a bit misleading? This may cause users to misunderstand that
>> such fsync can happen only in the case of crash recovery.
> 
> If I insert the following extra sentence after that one, is it better?
>   "This applies whenever starting a database cluster that did not shut
> down cleanly, including copies created with pg_basebackup."

Yes. Thanks!

Regards,

-- 
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION

Commits

  1. Change recovery_init_sync_method to PGC_SIGHUP.

  2. Provide recovery_init_sync_method=syncfs.